class Animal:
    def eat(self):
        print("吃")

    def drink(self):
        print("喝")

    def run(self):
        print("跑")

    def sleep(self):
        print("睡")


class Dog(Animal):
    def bark(self):
        print("汪汪叫")


if __name__ == '__main__':
    wang_cai = Animal()
    wang_cai.eat()

    xiao_gou = Dog()
    xiao_gou.sleep()
    xiao_gou.bark()
